Both the add and remove behavior you're describing is exactly what would 
happen if the load balancing was not sticky across 2 servers.  What kind 
of load balancer are you using?

I would try to confirm by creating a JSP like this:


and hit it repeatedly to confirm that stickiness is working.  I don't 
know the PHP syntax offhand to do the same, but just something to print 
the IP address of the server you hit.

Serge Knystautas
Lokitech >> software . strategy . design >>
p. 301.656.5501

Andrew Fritz wrote:
> It also just occurred to me that we have another problem that is 
> probably related (or in fact a result of the same root cause). To track 
> user log in we simply place their id into a variable in the $_SESSION 
> variable. If there is an ID in the session, that is the logged in user, 
> otherwise, the person isn't logged in. To log them out, we simple delete 
> this value. This fails randomly about 10% of the time (much more 
> commonly than the other bug being discussed here).
> So, the original bug seems to be related to inserting something into a 
> clustered session. The second bug is related to deleteting something 
> from a clustered session. It seems likely that there is some 
> synchronization/race condition between the servers that is resulting in 
> the server with outdated information occasionally "winning" and its 
> incorrect information to persist instead of the correct updated 
> information.
> Andrew

resin-interest mailing list

Reply via email to